Multiple-plane or user-enclosing rebound surfaces for practicing soccer or other sports

ABSTRACT

A sports device consisting of rebound surfaces facing in different directions, which will rebound a ball or other projectile propelled in one direction and also rebound a ball or other projectile propelled in at least one other different direction. The multiple rebound surfaces may form an enclosure consisting of four vertical surfaces with a rectangular footprint (see FIG.  1 ), usable for soccer practice, with multiple net surfaces ( 10 ) that rebound a soccer ball ( 16 ) kicked in any direction from the interior of the enclosure, back to the kicker.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Not Applicable

FEDERALLY SPONSORED RESEARCH

[0002] Not Applicable

SEQUENCE LISTING OR PROGRAM

[0003] Not Applicable

BACKGROUND OF THE INVENTION

[0004] 1. Field of Invention

[0005] This invention relates to devices used in training for the sportof soccer (known in most of the world as “football”), as well as othersports that involve propelling a projectile toward a goal, andparticularly to devices for rebounding a kicked soccer ball or otherpropelled projectile toward the kicker or other user to be kicked orstruck a second or additional times.

[0006] 2. Background of the Invention

[0007] Various products exists for training in soccer, as well as othersports, known as “rebounders” or “bounce-back” or “return” nets orgoals. When a practicing soccer player kicks a soccer ball into one ofthese devices, the device returns the ball to be kicked again. Suchdevices generally consist of a net with some elasticity, or otherrebound surface, tautly stretched across a frame of aluminum, some othermetal, PVC pipe or a similarly rigid material. These rebound devicesdiffer from a conventional soccer goal with a baggy net with slack init, in that the rebounder saves the user from having to retrieve theball after each kick. This allows many more touches on the ball in agiven period of time and thereby enhances soccer training. The same orsimilar products can be used for returning balls in other sports, forexample, returning a thrown baseball, softball, lacrosse ball orbasketball, or a struck tennis ball. These devices range in size fromthe full dimension of a standard soccer goal (8 feet high by 24 feetwide), to small devices such as 4 feet by 6 feet intended for backyarduse. They are often portable, with some method for holding them in placeduring use, such as metal J-hooks that clamp over the base of the frameand are driven into the ground, or ropes that attach to the frame andare tied down to anchoring pegs.

[0008] Various devices of this kind are sold by Kwik Goal Ltd, 140Pacific Drive Quakertown, Pa 18951, and can be seen at their web site atwww.kwikgoal.com; by Jafco Sports of Springfield, Mo.(www.soccerrebounder.com); and by Goal Sporting Goods, Inc., 37Industrial Park Road, Essex, Conn. 06426 (www.goalsports.com). One suchrebounder product is disclosed in U.S. Pat. No. 6,250,634 to Strain etal. (2001), a sports apparatus for bouncing back a sports object,consisting of an elastomeric sheet stretched across a frame. Another isa device that can be used either as a soccer goal or as a ball-returningpractice net for backyard use, disclosed in U.S. Pat. No. 4,083,561 toDaffer, Jr. (1978). A third is disclosed in U.S. Pat. No. 6,287,220issued to Caruso (2001), which dispenses with upper and lower frames,but stretches a net between two vertical uprights held in place with guyropes. U.S. Pat. No. 5,048,844 to Haseltine (1991) suggests a method ofcausing a ball struck along the ground into a net to rebound with anupward velocity component. A slightly different approach to the problemof returning a kicked ball to the kicker is disclosed by U.S. Pat. No.5,556,106 issued to Jurcisin (1996), which describes a solid verticalscreen that blocks the kicked balls, with a trough at the bottom thatcollects the kicked balls and funnels them to a conveyor that returnsthe balls to the kicker.

[0009] Another relevant device existing in prior art is the “battingcage” for practicing hitting in baseball or for practicing golf. Theseare commonly used to contain the ball struck by a batter or golfer. Thesurfaces of such cages generally consist of heavyweight knotted nylonnetting or similar material. These devices will contain a projectile,but differ from rebounders in that they are not designed to rebound theprojectile to the user. Cages of this kind made by Carron Net Company,Inc., 1623-17th Street, Two Rivers, Wis. can be seen at its web site athttp://www.carronnet.com/sportbw.pdf.

BACKGROUND OF THE INVENTION OBJECTS AND ADVANTAGES

[0010] All of the heretofore disclosed rebounder devices consist of arebounding target in a single plane, that is placed perpendicular to theline of travel of the ball between the kicker and the target. Thepresent invention differs from all these in that the user faces reboundsurfaces on multiple sides, and may be substantially surrounded byrebound surfaces. For example, in the preferred embodiment, the reboundsurfaces form an enclosure in the shape of a square, with each of foursides consisting of a rebounding net or other rebound surface. The userenters said enclosure through an opening and then closes the openingbehind the user. In the preferred embodiment this opening is made byattaching one of the rebound surfaces to its frame with Velcro strapsthat the user can remove to permit entry and then re-attach to close thedevice. Once inside, the training athlete may kick the ball in anydirection and have it returned by a rebound surface. This invention hasadvantages over the prior art of rebounders that are very significant intraining for the sport of soccer, including:

[0011] (a) the prior art only allows the kicker to practice kicking theball back in the direction from which it came, which is where therebounder net is placed; in actual soccer game situations, one oftenwants to kick the ball perpendicular to the direction of its arrival, aswhen shooting at the goal a ball that has been struck across the fieldby a teammate; one also often wishes to practice facing in one directionto receive a ball, and then turning 180 degrees to face the otherdirection and kick the ball; the present invention allows practicingboth these maneuvers, and indeed allows practicing repeatedly kickingthe ball at any angle in relation to its direction of arrival;

[0012] (b) with the prior rebounder art, if the kicker misses the goal,he is forced to retrieve the ball, wasting practice time; with thecurrent invention, the kicker is surrounded by rebound surfaces, soretrieving stray balls is eliminated; with the prior batting cage art,there is a complete enclosure that contains the projectile, but the ballis not returned to the kicker or other user; and

[0013] (c) a secondary use of the full enclosure embodiment of theinvention is as the scene for a game between two or more soccer players,in which goals are inserted within the enclosure at opposite ends, andkicking the ball off of the net walls or other rebound surfaces of theenclosure is permitted as a tactic in trying to pass the opponent andmove the ball toward the appropriate goal.

SUMMARY

[0014] A device to use in soccer training in which the athlete isconfronted on multiple sides, or substantially surrounded, by surfacesconsisting of a stretched net or other material that will cause a ballor other projectile to rebound when kicked or otherwise propelledagainst said surfaces. The surface or surfaces must be in at least twodifferent planes, and may substantially laterally enclose the user,forming a triangle, square, circle, or other geometric shape around theuser. (The term “laterally enclose” or “laterally surround” is usedthroughout this patent application to mean that rebound surfaces appearon substantially all sides of the user, but not below the user and notnecessarily above the user). Using the invention, a soccer player cankick the ball against a rebound surface, receive the ball back, and thenkick it again in a different direction against another rebound surfaceor a portion of the rebound surface in another plane. This device may beused to practice many soccer maneuvers, including kicking the ball atvarious angles to its line of arrival, such as 90 degrees, or turning180 degrees and kicking the ball in the same direction it was headingwhen it arrived at the kicker. In each case the ball or other projectileis captured by a rebound surface and therefore the user need not wastetime retrieving the ball. A teammate to feed the ball to the user isalso not necessary because the athlete can feed himself the ball bystriking it against one rebound surface which returns the ball to promptthe user's next action.

DRAWINGS

[0015]FIG. 1 shows the square enclosure embodiment of the invention,with a soccer player using it to strike the ball first in one directionagainst one surface, and then perpendicular to its path of return,against another surface.

[0016]FIG. 2 shows an alternative embodiment which does not form a fullenclosure, but consists of two vertical rebound nets at 90-degree anglesto each other.

DRAWINGS LIST OF REFERENCE NUMERALS

[0017]10 net rebound surface

[0018]12 guy rope supports

[0019]14 aluminum tubing frame member

[0020]16 soccer ball, arrow showing path

[0021]18 Velcro closure strips attaching net to frame

DETAILED DESCRIPTION

[0022] Preferred Embodiment

[0023] A preferred embodiment of the invention is illustrated in FIG. 1.The preferred embodiment is in the shape of a rectangular solid of whichthe base is 10 yards long and 10 yards wide and the height is eightfeet. The bottom surface of the device is open, so that when the devicerests on the ground, the bottom face consists of the turf or othersurface on which the device stands. In the preferred embodiment, the topsurface of the device is also open, although a top surface or roof maybe added to prevent escape of a ball or projectile. The preferredembodiment of the device has four vertical walls 10, each 10 yards wideand eight feet tall.

[0024] In the preferred embodiment, in each of the four corners at thebase of the rectangular solid shape stands a vertical frame element 14(in FIG. 1, for simplicity, the vertical frame element detail is shownonly in the right front corner of the device, or lower right corner ofthe page). In the preferred embodiment, the vertical frame element ismade of aluminum tubing with an outside diameter of two inches, butgalvanized steel tubing or poly vinyl chloride (“PVC”) pipe would alsoserve and the exact diameter may vary. The vertical frame tubes may bestabilized against lateral movement by placing the hollow tubing over astake partially driven into the ground. Each vertical frame tube isconnected at the top at right angles to two horizontal frame tubes thatconstitute top sides of the rectangular solid shape. The connectionsbetween frame pieces may be made by nuts and bolts or by sleeves thatlock into place with push buttons. The four vertical frame tubes areconnected by four horizontal frame tubes only at the top. There are noframe pieces running along the surface of the ground. If a permanentplacement of the invention is desired, 4-inch by 4-inch wood posts suchas are used in standard soccer goals could also be used as frame pieces.

[0025] In the preferred embodiment, each two adjacent vertical frametubes and the horizontal frame tube that connects them form a verticalsquare. The surface of this square consists of a net 10 attached at eachside to a vertical frame tube and at the top to the horizontal frametube. The net may be made of polypropylene or nylon with a one-inchsquare mesh. The net is attached to and stretched tautly between the twoadjacent vertical frame tubes, and is also attached to the horizontalframe tube above it. The attachments may be made by one-inch wide stripsof Velcro 18 wrapped through the border of the net and around the frametube. The net functions as the rebound surface that returns a ball orprojectile struck against it.

[0026] Additional stability of the device against lateral movementcaused by the impact of the ball or other projectile against thevertical rebound surface is provided by guy ropes 12 that attach at eachtop corner of the device, and are tied to stakes driven into the grounda few yards away.

[0027] Alternative Embodiments

[0028] The angle that the plane of each rebound surface makes with theground, ninety degrees in the preferred embodiment, can be varied, whichin turn varies the angle of flight of a ball as it returns to the user.In one embodiment, these angles at which the ball returns can be madevariable at the option of the user by movements of the frame tubing. Theangle of ball return can also be influenced by using a curved ratherthan straight frame to hold the net or other rebound surface.

[0029] In another alternative embodiment of the invention, there is anupper surface, top or roof to the lateral enclosure formed by therebound surfaces. This upper surface functions to prevent the escape ofa ball or projectile out of the enclosure. A disadvantage of thisembodiment is that the roof prevents kicking the ball to an indefiniteheight without interference, which limits some potential practiceapplications. The roof or upper surface may be made of a net similar tothe rebound surfaces or may be of any other material that will preventescape of a ball or projectile.

[0030] There are many alternatives to the rectangular solid shape of theenclosure shown in the preferred embodiment. In some of these, thedevice still consists of an enclosed space in which the user may besubstantially laterally surrounded by rebound surfaces. One example isan enclosure consisting of three vertical rebound surfaces, which can beat various angles to each other, such that a horizontal cross section ofthe enclosure would be in the shape of a triangle, as distinct from thefour vertical walls of the preferred embodiment shown in FIG. 1, ofwhich a horizontal cross-section is a square. Another alternativeembodiment is a rebounding surface in the shape of a cylindricalenclosure, in which the vertical rebound surface has a circular crosssection, and by which the user may be laterally surrounded.

[0031] Other alternative embodiments of the invention consist of aplurality of rebound surfaces in different planes that differ from thesingle-plane rebounders existing in prior art, but yet do not completelyenclose the user. For example, one alternative embodiment is a deviceconsisting of two vertical rebound surfaces, at 90 degrees to eachother, essentially the preferred embodiment with two sides removed. Thisis shown in FIG. 2. Such an embodiment would allow some but not all ofthe novel benefits of the preferred embodiment. For example, it wouldenable repeated practice in kicking a ball at a 90 degree angle to theball's direction of arrival at the user, but it would not facilitate theuser's practicing facing in one direction to receive the ball, and thenturning 180 degrees and kicking a ball in the same direction as that inwhich the ball is traveling on its arrival. Practice of this maneuver isenabled by a complete lateral enclosure such as that of the preferredembodiment shown in FIG. 1.

[0032] An noted, the preferred embodiment uses detachable Velcro straps18 to connect at least one of the rebound nets to the vertical framemember 14. It is by detaching these straps that the user gains entry toa device that laterally encloses the user. There is an alternative tothis method of opening and closing the enclosure. This is to attach theframes of two of the rebound surfaces to each other with hinges, so thatan entire side of the rebounding enclosure can be swung open and thenre-shut. This avoids the user's having to re-stretch the net to attachthe Velcro strips to re-close the device.

[0033] Operation of the Invention

[0034] In the preferred embodiment shown in FIG. 1, the user enters therectangular enclosure by removing the Velcro strips 18 that connect aportion of one net to its adjacent vertical tube frame 14, stepping intothe interior of the device, and then reconnecting the net using theVelcro strips. In the case of the alternative embodiment shown in FIG.2, in which there exist a sequence of connected rebound surfaces indifferent planes that do not completely enclose the user, the user cansimply step between the vertical rebound surfaces.

[0035] Once inside the enclosure (in the case of the preferredembodiment shown in FIG. 1), or between the vertical rebound surfaces(in the case of the alternative embodiment in which the device is notlaterally closed, as shown in FIG. 2), the practicing player can kick orotherwise propel the ball or other projectile in various directions,receive the ball back from the vertical rebound surface, and then kickor propel it again, either in the same direction or in a differentdirection. The invention can be used to practice many soccer maneuvers,including kicking the ball at various angles to its line of arrival,such as 90 degrees from the angle at which the ball arrives, or (in thecase of the preferred embodiment shown in FIG. 1) receiving the ballwhile facing in one direction and then turning 180 degrees and kickingthe ball in the same direction it was heading when the user received it.In each case the kicked or propelled ball or other projectile iscaptured by the vertical rebound surface and therefore the user need notwaste time going to retrieve the ball or projectile. The user of thedevice does not need another person to feed the ball because the usercan serve himself or herself the ball by striking it against thevertical rebound surface and awaiting its return. The device can also beused to practice heading or trapping a soccer ball by kicking it againstthe vertical rebound surface and then using the head or other body partsto strike or control the ball on its return.

[0036] The ball or other projectile can be kicked or otherwise propelledany number of times in a continuous fashion, to practice timing andintroduce an aerobic conditioning element to the practice session. Theuser of the device can follow a predetermined sequence of maneuvers, orone that is called out by a coach observing the practice session. Thefollowing are several examples of useful soccer practice routinesenabled by the invention:

[0037] (a) In a 4-surface enclosure such as the preferred embodimentshown in FIG. 1, the player kicks the ball against one rebound surface.When the ball returns, the player kicks it against a second reboundsurface, said second surface being the one adjacent to the first surfaceand in a clockwise direction from the first surface when viewed from theperspective of the user, so that the movement of the ball propelled bythe second kick is at a right angle to the direction of the first kick.When the ball returns after the second kick, the player kicks the ballagainst a third rebound surface, again moving in a clockwise direction,so that the direction of the third kick is 180 degrees opposite to thedirection of the first kick. When the ball returns after the third kick,the user kicks the ball a fourth time, this time against the onlyrebound surface against which it has not yet been kicked. When the ballreturns after the fourth kick, the user again kicks the ball against thesurface against which it was first kicked, thereby starting a secondrotation identical to the first. This rotation of four kicks against thefour different surfaces can repeated an indefinite number of times. Thisdrill enhances skill at kicking the ball at a 90-degree angle from itsdirection of arrival. The drill can be done with kicks in which the ballmaintains contact with the ground, or kicks in which the ball fliesthrough the air, to practice volleying (kicking an airborne ball) orhalf-volleying (kicking a ball just as it lands on the ground). The samedrill can be done moving counter-clockwise through the rebound surfaces,or alternating clockwise movement with counter-clockwise movement.

[0038] (b) In a 4-surface enclosure such as the preferred embodimentshown in FIG. 1, the user kicks the ball against one rebound surface.When the ball returns to the user, the user touches the ball with his orher foot in such a manner as to move the ball one or two yards in adirection perpendicular to the ball's path of arrival. The user thenturns 180 degrees and kicks the ball against the rebound surfacedirectly opposite the one to which the ball was originally directed.When the ball returns from the second kick, the player again touches theball slightly to the side and turns and kicks at the first reboundsurface. This sequence of 180 degree turns and kicks can be repeated anindefinite number of times. This drill enhances skill at rapidly turningwith the ball under control. Various alternative methods of turning withthe ball can be practiced, including lifting the ball with the foot,kicking it over the user's head and volleying it at the oppositesurface.

[0039] (c) In a 4-wall enclosure such as the preferred embodiment shownin FIG. 1, various combinations of the routines described in paragraphs(a) and (b) are possible, such as a clockwise 90-degree turn followed bya 180 degree turn, followed by another clockwise 90 degree turn andanother 180 turn, for an indefinite number of repetitions.

[0040] (d) In a 4-wall enclosure such as the preferred embodiment shownin FIG. 1, the rebound surfaces can be identified with the numbers onethrough four or in some other manner, and a coach standing outside theenclosure can call out the numbers or other identifiers in a randomsequence, with the user being required to direct the ball to theappropriate surface. This drill enhances skills similar to thosepracticed in the routines described in paragraphs (a) through (c), butbetter mimics a game situation by adding the additional challenge offorcing the user to respond to changing external circumstances.

[0041] (e) Using either the preferred embodiment shown in FIG. 1, or thealternative embodiment shown in FIG. 2, the player kicks the ballagainst one rebound surface. When the ball returns, the player kicks itagainst the next rebound surface, moving in a clockwise direction, sothat the movement of the ball propelled by the second kick is at a rightangle to direction of the first kick. When the ball returns after thesecond kick, the player this time turns counterclockwise and again kicksthe ball against the rebound surface to which the first kick wasdirected. The player repeats this sequence turning to the right and thenback to the left repeatedly. This drill enhances development of rhythmand if continued can be an excellent aerobic exercise. Again, the ballcan be struck either in the ground or in the air. Also, variouscombinations of left-footed and right-footed kicks are possible, as arekicks with the various parts of the foot—the shoelace, the inside of thefoot, outside of the foot and heel.

[0042] None of the practice routines described above are possible usingthe prior art. Many other novel practice techniques are also enabled bythe invention. Those noted above are merely illustrative.

[0043] In addition to practice drills for individuals such as thosedescribed above, the invention also enables a novel form of competitivegame between two or more soccer players. This game would be playedwithin a 4-surface rectangular enclosure of perhaps 10 yards width and20 yards length, similar to FIG. 1 except with one side elongated.Goals, perhaps 4 feet high and 6 feet wide, are inserted within theenclosure at opposite ends of the enclosure, each just in front of themiddle of one of the 10-yard wide rebound surfaces. In a 20-yard longenclosure, then, the goals would be slightly less than 20 yards apart.One player attempts to score by kicking the ball into one goal and theother player attempts to score by kicking the ball into the other goal.The players are permitted to kick the ball against the nets or otherrebound surfaces at the sides or ends of the enclosure, with the resultthat the ball rebounds into the enclosure, and the players may use suchrebounding kicks as a tactic in attempting to pass the opponent and movetoward the appropriate goal.

[0044] In addition to enabling novel practice drills for individuals andthe novel form of game described in the preceding paragraph, the currentinvention can serve as a practice tool for sports other than soccer thatalso involve propelling a projectile toward a goal, such as lacrosse,hockey and basketball. In this application, the device is used in amanner analogous to the soccer practice drills described above, exceptthat instead of kicking a soccer ball, the user throws or strikes alacrosse ball, hockey puck or basketball against the rebound surface.Some variation in materials might be necessary for such other sports,such as using net with a different mesh size, or a different reboundsurface. In addition to the practice applications for other sports, amulti-person game analogous to that described in the preceding paragraphis also possible for other sports that involve propelling a projectileinto a goal.

[0045] Advantages

[0046] Advantages of the invention include:

[0047] (a) It allows practicing repeated kicking or heading of a soccerball (or throwing or striking another kind of ball or projectile) at anyangle in relation to the ball or other projectile's direction ofarrival;

[0048] (b) it allows practicing trapping and controlling a soccer ballcoming from any direction;

[0049] (c) it retains a kicked or otherwise struck ball or otherprojectile near the user to avoid wasting time retrieving the ball orprojectile;

[0050] (d) in addition to being usable as a training device by anindividual, the invention enables a soccer competition between two ormore users in which kicking the ball against the nets or other reboundsurfaces of an enclosure is possible, or an analogous competition forother sports in which throwing or striking the ball or other projectileagainst the nets or other rebound surfaces of an enclosure is possible.

I claim:
 1. A device for use in sports practice or games, including oneor more surfaces that will cause a ball or other projectile to reboundfrom the surface, said device having at least one such rebound surfaceor portion of a rebound surface that is in a different plane from atleast one other such rebound surface or portion of a rebound surface ofthe device, whereby a user of the device may propel a ball or otherprojectile against one surface or portion of a surface of the device,and upon the return of the ball or other projectile from said surface orportion of a surface of the device, the user may then propel said ballor other projectile in a different direction against a second reboundsurface or portion of a rebound surface of the device, said secondrebound surface or portion of a rebound surface being in a differentplane from the first surface or portion of surface struck by the ball orother projectile.
 2. The device of claim 1, wherein a plurality ofsubstantially vertical rebound surfaces, or portions of a reboundsurface, are arranged in a substantially closed geometric shape, wherebya user of the device may enter and be substantially laterally surroundedby such rebound surfaces.
 3. The device of claim 1, wherein a pluralityof substantially vertical rebound surfaces, or portions of a reboundsurface, are arranged in the shape of a rectangular solid, whereby auser of the device may enter and be substantially laterally surroundedby such rebound surfaces.
 4. The device of claim 1, wherein theplurality of rebound surfaces, or portions of a rebound surface, arearranged in the shape of a triangular solid, whereby a user of thedevice may enter and be substantially laterally surrounded by suchrebound surfaces.
 5. The device of claim 1, wherein the rebound surfaceis in the shape of a cylinder, whereby a user of the device may enterand be substantially laterally surrounded by such rebound surface. 6.The device of claim 1, wherein the angle made by the intersection of (a)the plane in which one or more rebound surfaces lies and (b) the planein which the ground underneath the device lies, may be adjusted by theuser, whereby a ball or other projectile struck at the rebound surfacereturns to the user at a different angle.
 7. The device of claim 2,wherein the substantially closed geometric shape formed by the verticalrebound surfaces, is covered by a net or other device that along withsaid vertical rebound surfaces forms an enclosure preventing escape of aball or projectile.
 8. The device of claim 3, wherein the rectangularsolid shape formed by the vertical rebound surfaces is covered by a netor other device that along with said vertical rebound surfaces forms anenclosure preventing escape of a ball or projectile.
 9. The device ofclaim 4, wherein the triangular solid shape formed by the verticalrebound surfaces is covered by a net or other device that along withsaid vertical rebound surfaces forms an enclosure preventing escape of aball or projectile.
 10. The device of claim 5, wherein the cylindricalshape formed by the vertical rebound surface is covered by a net orother device that along with said vertical rebound surface forms anenclosure preventing escape of a ball or projectile.
 11. The device ofclaim 1, wherein at least one rebound surface is a net.
 12. The deviceof claim 1, wherein the perimeter of at least one rebound surface isbounded by a solid frame.
 13. The device of claim 12, wherein the frameof at least one rebound surface is made of aluminum, galvanized steel orpoly vinyl chloride.
 14. The device of claim 12, wherein (a) theelements of the frames of the rebound surface or surfaces consist oftubing; (b) said tubing frame elements are interconnected by inserting asmaller-diameter portion of one tubing frame element into alarger-diameter sleeve of another tubing frame element; (c) saidsmaller-diameter portion of said first tubing frame element bears aretractable button perpendicular to the surface of the tubing; (d) saidsmaller-diameter portion of said first tubing frame element also bears aspring that exerts outward pressure on the retractable button; and (e)said larger-diameter sleeve of said second tubing frame element containsa hole through which said retractable button can fit; whereby once saidsmaller-diameter portion of the first tubing frame element is insertedto the properly assembled position within said larger-diameter sleeve ofsaid second tubing frame element, said spring causes said retractedbutton on said first tubing frame element to emerge through thecorresponding hole in said larger-diameter portion of said second tubingframe element, thereby locking the two tubing frame elements into place.15. A method of training for a sport involving the kicking, throwing,striking or other propelling of a ball or other projectile, in which:(a) the athlete positions himself or herself between a plurality ofsurfaces or portions of surfaces that will cause a ball or otherprojectile struck against them to rebound from such surfaces or portionsof surfaces; and (b) at least one such rebound surface or portion of arebound surface is in a different plane from at least one other suchrebound surface or portion of a rebound surface; whereby the athletesequentially propels a ball or other projectile in at least twodifferent directions against such surfaces or portions of surfaces. 16.The method of claim 15 in which said sport is soccer and said ball iskicked.
 17. The method of claim 15 in which said sport is soccer andsaid ball is struck with the athlete's head.